Heteroepitaxial Growth of Planar Semipolar (101̄1) GaN by Metalorganic Vapor Phase Epitaxy

We report on the growth of planar semipolar (101̄1) GaN on (112̄3) pre-patterned sapphire. This method allows the growth of semipolar oriented (101̄1) GaN on large scale. By x-ray diffaction, only the peaks of the desired (101̄1) plane could be observed. The in-plane orientations could be determined as [0001]GaN ‖ [0001]sapphire and [112̄0]GaN ‖ [101̄0]sapphire. Scanning electron microscopy, transmission electron microscopy and atomic force microscopy measurements show coalesced surfaces with root mean square roughness values below 2 nm (10μm×10μm). Further investigations using photoluminescence spectroscopy show spectra that are dominated by the near band edge emission. The high crystal quality is confirmed by small full width at half maximum values of x-ray rocking curve measurements of less than 400 arcsec.